Fuel injection valves for a high pressure as well as a low pressure direct fuel injection are basically known in the state of the art. They are typically designed as solenoid-controlled valves or piezo valves.
Fuel injection valves allocate the fuel mass to be injected into the cylinder, which is required for a clean and efficient combustion in the engine. The actuation of the fuel injection valves occurs typically by way of a power output stage, whereby the fuel injection is activated preferably by means of a so-called low side switch of the output stage.
The output stage is monitored during the operation so that short circuits are discovered to the battery terminal voltage and to ground of the output stage, and a response can be made to them.
From the German patent DE 102 34 091 A1, a procedure is, for example, known to monitor at least two electromagnetic valves. In the aforesaid procedure, the current supplied to the valves is measured and compared with a set point current. If the difference between the set point current and the actual current exceeds a threshold value, this is then recognized as a malfunction.
From the German patent DE 40 12 109 A1 a device is known for the functional monitoring of an electrical output stage, in which an error acquisition logic is connected in parallel to the output stage. Provision is made for the error acquisition logic to apply suitable electric potentials at different terminals of the output stage for the identification of an existing error in order, for example, to be able to differentiate an overload or short circuit to ground or to the positive terminal or additional possibilities of error.